Gando, A. and Grant, C. and Dwyer, D. A. and McKeown, R. D. and Zhang, C. (2011) Constraints on θ_(13) from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND. Physical Review D, 83 (5). Art. No. 052002. ISSN 0556-2821 http://resolver.caltech.edu/CaltechAUTHORS:20110328-105839177
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We present new constraints on the neutrino oscillation parameters Δm^2_(21), θ_(12), and θ_(13) from a three flavor analysis of solar and KamLAND data. The KamLAND data set includes data acquired following a radiopurity upgrade and amounts to a total exposure of 3.49 x 10^(32) target-proton-year. Under the assumption of CPT invariance, a two-flavor analysis (θ_(13) = 0) of the KamLAND and solar data yields the best-fit values tan^2θ_(12) = 0.444^(+0.036)_(-0.030) and Δm^2_(21) = 7.50^(+0.19)_(-0.20) x 10^(-5) eV^2; a three-flavor analysis with θ13 as a free parameter yields the best-fit values tan^2θ_(12) = 0.452^(+0.035)_(-0.033), Δm^2_(21) = 7.50^(+0.19)_(-0.20) x 10^(-5) eV^2, and sin^2θ_(13) = 0.020^(+0.016)_(-0.016). This θ_(13) interval is consistent with other recent work combining the CHOOZ, atmospheric and long-baseline accelerator experiments. We also present a new global θ_(13) analysis, incorporating the CHOOZ, atmospheric, and accelerator data, which indicates sin^2θ_(13) = 0.009^(+0.013)-_(0.007). A nonzero value is suggested, but only at the 79% C.L.
|Additional Information:||© 2011 American Physical Society. Received 25 September 2010; published 4 March 2011. The KamLAND experiment is supported by the Grantin-Aid for Specially Promoted Research under Grant No. 16002002 of the Japanese Ministry of Education, Culture, Sports, Science and Technology; the World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan; and under the U.S. Department of Energy (DOE) Grants No. DE-FG03-00ER41138, DEAC02- 05CH11231, and DE-FG02-01ER41166, as well as other DOE grants to individual institutions. The reactor data are provided by courtesy of the following electric associations in Japan: Hokkaido, Tohoku, Tokyo, Hokuriku, Chubu, Kansai, Chugoku, Shikoku, and Kyushu Electric Power Companies, Japan Atomic Power Company, and Japan Atomic Energy Agency. The Kamioka Mining and Smelting Company has provided service for activities in the mine.|
|Classification Code:||PACS: 14.60.Pq, 26.65.+t, 28.50.Hw, 91.35.-x|
|Official Citation:||Constraints on θ13 from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND A. Gando et al. (The KamLAND Collaboration) Published 4 March 2011 (11 pages) 052002|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||28 Mar 2011 21:22|
|Last Modified:||26 Dec 2012 13:07|
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